1. Field of the Invention
The present invention relates to novel vehicles based on a latex of acrylic type for aqueous emulsion (or dispersion) paints.
2. Description of the Prior Art
Paints of the above type are well known to this art and are widely described in the literature, patent and otherwise.
One of the major problems encountered in this type of paint, which is formulated with a low vehicle content (PVC&gt;critical PVC) (PVC=pigment volume concentration), is their wet abrasion resistance, hereinafter designated WAR. Measurement of the WAR enables determination of the washability or the wash-fastness of paints.
This art is replete with various attempts to improve the WAR. Thus, U.S. Pat. No. 4,169,086 describes the addition of a particular salt of an acyl ester of hydroxymethane phosphonic acid.
EP-A-9,110 describes the addition of a polyglycidyl compound to the paint with a view to improving the WAR.
EP-A-69,326, with the object of improving wet adhesion on an alkyd background, describes the addition of 0.2% to 10% by weight of a glycidyl ether which has an epoxy value of 0.1 to 0.8 in 90% to 99.8% by weight of an aqueous dispersion of a vinyl latex, to a paint having a high vehicle content (PVC&lt;critical PVC).
The glycidyl ether, employed as such and not in aqueous dispersion in the vinyl latex, is the product of reaction of epichlorohydrin with an aliphatic alcohol which itself preferably contains an ethoxy group.
The aqueous dispersion obtained undoubtedly exhibits improved wet adhesion, but it is well known to this art that the introduction of an epoxy resin into the aqueous latex dispersion is difficult and the paint thus obtained exhibits insufficient stability in storage.